X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/48e671d5303c70deea9cde5c1a785882c0501f6e..HEAD:/hostfile.c diff --git a/hostfile.c b/hostfile.c index 831ac592..cd28bf44 100644 --- a/hostfile.c +++ b/hostfile.c @@ -1,99 +1,161 @@ +/* $OpenBSD: hostfile.c,v 1.46 2009/10/11 23:03:15 djm Exp $ */ /* - * - * hostfile.c - * * Author: Tatu Ylonen - * * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved - * - * Created: Thu Jun 29 07:10:56 1995 ylo - * * Functions for manipulating the known hosts files. - * + * + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + * + * + * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved. + * Copyright (c) 1999 Niels Provos. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" -RCSID("$OpenBSD: hostfile.c,v 1.11 2000/01/04 00:07:59 markus Exp $"); -#include "packet.h" -#include "ssh.h" +#include -/* - * Reads a multiple-precision integer in hex from the buffer, and advances - * the pointer. The integer must already be initialized. This function is - * permitted to modify the buffer. This leaves *cpp to point just beyond the - * last processed (and maybe modified) character. Note that this may modify - * the buffer containing the number. - */ +#include -int -auth_rsa_read_bignum(char **cpp, BIGNUM * value) -{ - char *cp = *cpp; - int len, old; +#include +#include - /* Skip any leading whitespace. */ - for (; *cp == ' ' || *cp == '\t'; cp++) - ; +#include +#include +#include +#include +#include - /* Check that it begins with a hex digit. */ - if (*cp < '0' || *cp > '9') - return 0; +#include "xmalloc.h" +#include "match.h" +#include "key.h" +#include "hostfile.h" +#include "log.h" - /* Save starting position. */ - *cpp = cp; +static int +extract_salt(const char *s, u_int l, char *salt, size_t salt_len) +{ + char *p, *b64salt; + u_int b64len; + int ret; - /* Move forward until all hex digits skipped. */ - for (; *cp >= '0' && *cp <= '9'; cp++) - ; + if (l < sizeof(HASH_MAGIC) - 1) { + debug2("extract_salt: string too short"); + return (-1); + } + if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { + debug2("extract_salt: invalid magic identifier"); + return (-1); + } + s += sizeof(HASH_MAGIC) - 1; + l -= sizeof(HASH_MAGIC) - 1; + if ((p = memchr(s, HASH_DELIM, l)) == NULL) { + debug2("extract_salt: missing salt termination character"); + return (-1); + } - /* Compute the length of the hex number. */ - len = cp - *cpp; + b64len = p - s; + /* Sanity check */ + if (b64len == 0 || b64len > 1024) { + debug2("extract_salt: bad encoded salt length %u", b64len); + return (-1); + } + b64salt = xmalloc(1 + b64len); + memcpy(b64salt, s, b64len); + b64salt[b64len] = '\0'; + + ret = __b64_pton(b64salt, salt, salt_len); + xfree(b64salt); + if (ret == -1) { + debug2("extract_salt: salt decode error"); + return (-1); + } + if (ret != SHA_DIGEST_LENGTH) { + debug2("extract_salt: expected salt len %d, got %d", + SHA_DIGEST_LENGTH, ret); + return (-1); + } - /* Save the old terminating character, and replace it by \0. */ - old = *cp; - *cp = 0; + return (0); +} - /* Parse the number. */ - if (BN_dec2bn(&value, *cpp) == 0) - return 0; +char * +host_hash(const char *host, const char *name_from_hostfile, u_int src_len) +{ + const EVP_MD *md = EVP_sha1(); + HMAC_CTX mac_ctx; + char salt[256], result[256], uu_salt[512], uu_result[512]; + static char encoded[1024]; + u_int i, len; + + len = EVP_MD_size(md); + + if (name_from_hostfile == NULL) { + /* Create new salt */ + for (i = 0; i < len; i++) + salt[i] = arc4random(); + } else { + /* Extract salt from known host entry */ + if (extract_salt(name_from_hostfile, src_len, salt, + sizeof(salt)) == -1) + return (NULL); + } - /* Restore old terminating character. */ - *cp = old; + HMAC_Init(&mac_ctx, salt, len, md); + HMAC_Update(&mac_ctx, host, strlen(host)); + HMAC_Final(&mac_ctx, result, NULL); + HMAC_cleanup(&mac_ctx); - /* Move beyond the number and return success. */ - *cpp = cp; - return 1; + if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || + __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) + fatal("host_hash: __b64_ntop failed"); + + snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt, + HASH_DELIM, uu_result); + + return (encoded); } /* - * Parses an RSA key (number of bits, e, n) from a string. Moves the pointer - * over the key. Skips any whitespace at the beginning and at end. + * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the + * pointer over the key. Skips any whitespace at the beginning and at end. */ int -auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n) +hostfile_read_key(char **cpp, u_int *bitsp, Key *ret) { - unsigned int bits; char *cp; /* Skip leading whitespace. */ for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) ; - /* Get number of bits. */ - if (*cp < '0' || *cp > '9') - return 0; /* Bad bit count... */ - for (bits = 0; *cp >= '0' && *cp <= '9'; cp++) - bits = 10 * bits + *cp - '0'; - - /* Get public exponent. */ - if (!auth_rsa_read_bignum(&cp, e)) - return 0; - - /* Get public modulus. */ - if (!auth_rsa_read_bignum(&cp, n)) + if (key_read(ret, &cp) != 1) return 0; /* Skip trailing whitespace. */ @@ -102,67 +164,23 @@ auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n) /* Return results. */ *cpp = cp; - *bitsp = bits; + *bitsp = key_size(ret); return 1; } -/* - * Tries to match the host name (which must be in all lowercase) against the - * comma-separated sequence of subpatterns (each possibly preceded by ! to - * indicate negation). Returns true if there is a positive match; zero - * otherwise. - */ - -int -match_hostname(const char *host, const char *pattern, unsigned int len) +static int +hostfile_check_key(int bits, const Key *key, const char *host, const char *filename, int linenum) { - char sub[1024]; - int negated; - int got_positive; - unsigned int i, subi; - - got_positive = 0; - for (i = 0; i < len;) { - /* Check if the subpattern is negated. */ - if (pattern[i] == '!') { - negated = 1; - i++; - } else - negated = 0; - - /* - * Extract the subpattern up to a comma or end. Convert the - * subpattern to lowercase. - */ - for (subi = 0; - i < len && subi < sizeof(sub) - 1 && pattern[i] != ','; - subi++, i++) - sub[subi] = isupper(pattern[i]) ? tolower(pattern[i]) : pattern[i]; - /* If subpattern too long, return failure (no match). */ - if (subi >= sizeof(sub) - 1) - return 0; - - /* If the subpattern was terminated by a comma, skip the comma. */ - if (i < len && pattern[i] == ',') - i++; - - /* Null-terminate the subpattern. */ - sub[subi] = '\0'; - - /* Try to match the subpattern against the host name. */ - if (match_pattern(host, sub)) { - if (negated) - return 0; /* Fail */ - else - got_positive = 1; - } + if (key == NULL || key->type != KEY_RSA1 || key->rsa == NULL) + return 1; + if (bits != BN_num_bits(key->rsa->n)) { + logit("Warning: %s, line %d: keysize mismatch for host %s: " + "actual %d vs. announced %d.", + filename, linenum, host, BN_num_bits(key->rsa->n), bits); + logit("Warning: replace %d with %d in %s, line %d.", + bits, BN_num_bits(key->rsa->n), filename, linenum); } - - /* - * Return success if got a positive match. If there was a negative - * match, we have already returned zero and never get here. - */ - return got_positive; + return 1; } /* @@ -170,27 +188,29 @@ match_hostname(const char *host, const char *pattern, unsigned int len) * in the list of our known hosts. Returns HOST_OK if the host is known and * has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED * if the host is known but used to have a different host key. + * + * If no 'key' has been specified and a key of type 'keytype' is known + * for the specified host, then HOST_FOUND is returned. */ -HostStatus -check_host_in_hostfile(const char *filename, const char *host, - BIGNUM * e, BIGNUM * n, BIGNUM * ke, BIGNUM * kn) +static HostStatus +check_host_in_hostfile_by_key_or_type(const char *filename, + const char *host, const Key *key, int keytype, Key *found, int *numret) { FILE *f; char line[8192]; int linenum = 0; - unsigned int bits, kbits, hostlen; - char *cp, *cp2; + u_int kbits; + char *cp, *cp2, *hashed_host; HostStatus end_return; + debug3("check_host_in_hostfile: host %s filename %s", host, filename); + /* Open the file containing the list of known hosts. */ f = fopen(filename, "r"); if (!f) return HOST_NEW; - /* Cache the length of the host name. */ - hostlen = strlen(host); - /* * Return value when the loop terminates. This is set to * HOST_CHANGED if we have seen a different key for the host and have @@ -198,10 +218,7 @@ check_host_in_hostfile(const char *filename, const char *host, */ end_return = HOST_NEW; - /* size of modulus 'n' */ - bits = BN_num_bits(n); - - /* Go trough the file. */ + /* Go through the file. */ while (fgets(line, sizeof(line), f)) { cp = line; linenum++; @@ -217,8 +234,18 @@ check_host_in_hostfile(const char *filename, const char *host, ; /* Check if the host name matches. */ - if (!match_hostname(host, cp, (unsigned int) (cp2 - cp))) - continue; + if (match_hostname(host, cp, (u_int) (cp2 - cp)) != 1) { + if (*cp != HASH_DELIM) + continue; + hashed_host = host_hash(host, cp, (u_int) (cp2 - cp)); + if (hashed_host == NULL) { + debug("Invalid hashed host line %d of %s", + linenum, filename); + continue; + } + if (strncmp(hashed_host, cp, (u_int) (cp2 - cp)) != 0) + continue; + } /* Got a match. Skip host name. */ cp = cp2; @@ -227,19 +254,28 @@ check_host_in_hostfile(const char *filename, const char *host, * Extract the key from the line. This will skip any leading * whitespace. Ignore badly formatted lines. */ - if (!auth_rsa_read_key(&cp, &kbits, ke, kn)) + if (!hostfile_read_key(&cp, &kbits, found)) continue; - if (kbits != BN_num_bits(kn)) { - error("Warning: %s, line %d: keysize mismatch for host %s: " - "actual %d vs. announced %d.", - filename, linenum, host, BN_num_bits(kn), kbits); - error("Warning: replace %d with %d in %s, line %d.", - kbits, BN_num_bits(kn), filename, linenum); + if (numret != NULL) + *numret = linenum; + + if (key == NULL) { + /* we found a key of the requested type */ + if (found->type == keytype) { + fclose(f); + return HOST_FOUND; + } + continue; } + + if (!hostfile_check_key(kbits, found, host, filename, linenum)) + continue; + /* Check if the current key is the same as the given key. */ - if (BN_cmp(ke, e) == 0 && BN_cmp(kn, n) == 0) { + if (key_equal(key, found)) { /* Ok, they match. */ + debug3("check_host_in_hostfile: match line %d", linenum); fclose(f); return HOST_OK; } @@ -260,47 +296,58 @@ check_host_in_hostfile(const char *filename, const char *host, return end_return; } +HostStatus +check_host_in_hostfile(const char *filename, const char *host, const Key *key, + Key *found, int *numret) +{ + if (key == NULL) + fatal("no key to look up"); + return (check_host_in_hostfile_by_key_or_type(filename, host, key, 0, + found, numret)); +} + +int +lookup_key_in_hostfile_by_type(const char *filename, const char *host, + int keytype, Key *found, int *numret) +{ + return (check_host_in_hostfile_by_key_or_type(filename, host, NULL, + keytype, found, numret) == HOST_FOUND); +} + /* * Appends an entry to the host file. Returns false if the entry could not * be appended. */ int -add_host_to_hostfile(const char *filename, const char *host, - BIGNUM * e, BIGNUM * n) +add_host_to_hostfile(const char *filename, const char *host, const Key *key, + int store_hash) { FILE *f; - char *buf; - unsigned int bits; + int success = 0; + char *hashed_host = NULL; - /* Open the file for appending. */ + if (key == NULL) + return 1; /* XXX ? */ f = fopen(filename, "a"); if (!f) return 0; - /* size of modulus 'n' */ - bits = BN_num_bits(n); - - /* Print the host name and key to the file. */ - fprintf(f, "%s %u ", host, bits); - buf = BN_bn2dec(e); - if (buf == NULL) { - error("add_host_to_hostfile: BN_bn2dec(e) failed"); - fclose(f); - return 0; - } - fprintf(f, "%s ", buf); - free(buf); - buf = BN_bn2dec(n); - if (buf == NULL) { - error("add_host_to_hostfile: BN_bn2dec(n) failed"); - fclose(f); - return 0; + if (store_hash) { + if ((hashed_host = host_hash(host, NULL, 0)) == NULL) { + error("add_host_to_hostfile: host_hash failed"); + fclose(f); + return 0; + } } - fprintf(f, "%s\n", buf); - free(buf); + fprintf(f, "%s ", store_hash ? hashed_host : host); - /* Close the file. */ + if (key_write(key, f)) { + success = 1; + } else { + error("add_host_to_hostfile: saving key in %s failed", filename); + } + fprintf(f, "\n"); fclose(f); - return 1; + return success; }